This invention is in the field of monitoring techniques and relates to a method and device for monitoring the patient""s bladder urine distention level, which is particularly useful in preventing of bedwetting.
Bedwetting (involuntary enuresis) is a known problem, and various methods of treatment have been applied to patients suffering from this problem. According to statistical studies, bedwetting has an overall prevalence of up to 1% among the general population and up to 3% in late adolescence.
Various techniques aimed at solving this problem have been developed, and are disclosed, for example, in U.S. Pat. Nos. 4,347,503; 4,738,260; 4,977,906 and 5,036,859. All of them utilize a sensing pad for detecting the existence of initial drops of urine.
One of the most popular commercially available devices comprises a sensor of the type capable of detecting the existence of moisture, and an audio indicator coupled to the sensor through a wire. The patient attaches the device and puts it in operation just before going to bed. Upon detecting the initial drop(s) of urine, the sensor generates a signal which actuates the indicator to produce an alarm audio signal aimed at waking the patient.
U.S. Pat. Nos. 4,926,871 and 5,058,591 disclose techniques for the non-invasive automatic measurement of the volume of a human urine bladder. The technique disclosed in US ""871 utilizes an ultrasonic transducer performing imaging of the urine bladder by means of transmitting a plurality of ultrasound signals into orthogonal planes. The technique disclosed in US ""591 is based on the use of an ultrasonic transducer, which is attached to the patient""s abdomen and performs a scanning of the urine bladder to obtain information indicative of its diameter, namely the space between the bladder""s front and rear walls. The ultrasonic transducer is associated with a power source and is coupled to a suitable microprocessor. The microprocessor is preprogrammed for analyzing the information received from the transducer, and is capable of, upon detecting that the urine bladder""s diameter has reached a predetermined, critical value, generating a signal indicative thereof. This signal is transmitted to a suitable alarm output circuit.
However, such an ultrasonic transducer, whose operational frequency is typically more that 20 kHz (as specifically indicated in US ""591, the frequency of sound waves is 0.5 MHz), requires a voltage supply of up to 50V (12V, as indicated in this patent). This significantly increases the price of the entire device. Moreover, it is obvious, and specifically indicated in the patent, that the output of the receiver needs to be reduced to the range of 0-5V, thereby requiring an additional transformer, which both increases the price and complicates the construction of the device. Furthermore, it is understood that the power source supplying 12V has dimensions that do not allow miniaturization of the device, and its high price would not allow for making it a disposable device. It is clear from the illustrations in the patent that the dimensions of the sensor device are in the same order of those of the patient""s urine bladder.
U.S. Pat. No. 5,239,997 discloses the use of low frequency sound waves for detecting abnormalities and quantification of defects in the portion of a human body. Here, the low frequency sound waves are applied such as to provide imitation of the effect of direct percussion on the body part to be examined.
There is accordingly a need in the art to facilitate the monitoring of bladder urine distention level to prevent bedwetting, by providing a novel device and method therefor.
It is a major feature of the present invention to provide such a device which is miniature, requiring a small amount of energy supply and easy to attach to the patient""s body.
It is a further feature of the present invention to provide such a device which has a low cost and may therefore be disposable.
The main idea of the present invention is based on the following. To facilitate detecting the condition of the patient""s urine bladder just prior to the need to urinate, there is actually no need for imaging the bladder itself. It is sufficient to collect signals reflected from the urine-containing bladder to estimate the current level (amount) of urine in the bladder. In other words, the complicated and expensive sensor-battery assembly used in the ultrasonic-based imaging technique can be replaced by a relatively inexpensive and portable assembly utilizing a sensor operating with acoustic waves in the frequency ranges of audio (16 Hz-20 kHz) or infrasound (less than 16 Hz) signals, which requires a relatively low power supply, as compared to that of the ultrasonic sensor. Consequently, such an inexpensive assembly may be disposable. If it is disposable, it may be designed like a piece of patch.
There is thus provided according to one aspect of the present invention, a device for monitoring the condition of bladder urine distention level of a patient, the device comprising:
(a) a sensing unit for attaching to a certain location on the patient""s abdomen, the sensing unit being of the kind which transmits acoustic signals substantially not exceeding 20 kHz to the urine bladder through the patient""s tissue, receives signals reflected from the urine bladder, and generates data representative of the condition of the bladder urine distention level;
(b) a processor responsive to said data for analyzing the data and selectively generating a signal indicative of the existence of the predetermined condition of the patient""s bladder urine distention level; and
(c) an indication unit responsive to said signal indicative of the existence of the predetermined condition for generating an indication signal to attract the attention of an authorized person.
According to another aspect of the present invention, there is provided a method for monitoring the condition of a patient""s bladder urine distention level, the method comprising the steps of:
(i) attaching to a certain location of the patient""s abdomen a sensing unit of the kind capable of transmitting acoustic signals substantially not exceeding 20 kHz to the urine bladder through tissue, receiving signals reflected from the urine bladder, and generating data representative of the condition of the bladder urine distention level;
(ii) actuating the sensing unit for transmitting said acoustic signals;
(iii) receiving and analyzing said data representative of the condition of the bladder urine distention level;
(iv) upon detecting that said data is indicative of the existence of a predetermined condition, generating an indication signal.
According to yet another embodiment of the invention, there is provided a device for monitoring the condition of bladder urine distention level of a patient, the device comprising:
a sensing assembly, a processor and an indication assembly accommodated in a substantially flat flexible case having one surface thereof coated with a gluing material for attaching the case to a certain location on the patient""s abdomen, wherein
the sensing assembly is of a kind capable of transmitting acoustic signals substantially not exceeding 20 kHz to the urine bladder through the patient""s tissue, receiving signals reflected from the urine bladder and generating data representative of the condition of the bladder urine distention level,
the processor is responsive to said data for analyzing the data and selectively generating a signal indicative of the existence of the predetermined condition of the patient""s bladder urine distention level, and
the indication assembly is responsive to said signal indicative of the existence of the predetermined condition for generating an indication signal to attract the attention of an authorized person.